Rocket landing systems

ABSTRACT

A rocket landing stabilization system can include one or more upright support structures such as posts, columns, or walls, from which one or more stabilizing elements can be supported. The stabilizing elements can be used to stabilize a rocket as it lands at a landing site. The rocket landing stabilization system can also include a cradle, funnel, or cone to catch or otherwise support a rocket as it lands at the landing site. The rocket landing stabilization system can be located on land or at sea.

BACKGROUND Technical Field

The present disclosure relates to systems for safely landing a rocket ora rocket booster for reuse, for example, after the rocket booster hasbeen used to launch a payload into outer space.

Description of the Related Art

Since the dawn of the space age and the launching of Sputnik into outerspace, various rockets have been used to launch cargo, animals, andhumans into outer space. After carrying their payload to the edge of orinto outer space, the rockets or rocket boosters have fallen back toearth only to crash into the ground or the ocean and as a result aredestroyed. In recent years, some have attempted to bring rocket boostersback safely from their mission so they can be reused. Some believe thatreusable rockets or rocket boosters could reduce the costs associatedwith launching objects into outer space significantly. Example rocketlanding techniques are shown and described in U.S. Pat. No. 8,678,321,which is incorporated herein by reference in its entirety.

BRIEF SUMMARY

A rocket landing stabilization system can comprise a funnel sized toreceive a landing rocket and a stabilization structure positioned abovethe funnel. The stabilization structure can include a first lateralsupport cable, a second lateral support cable spaced apart from thefirst lateral support cable, a first stabilization cable coupled to thefirst lateral support cable and coupled to the second lateral supportcable, and a second stabilization cable coupled to the first lateralsupport cable and coupled to the second lateral support cable. The firststabilization cable can be adjustable with respect to the secondstabilization cable along the first lateral support cable and along thesecond lateral support cable. The first lateral support cable can becoupled to a first upright support structure and the second lateralsupport cable can be coupled to a second upright support structure. Thefirst and second upright support structures can be columns or walls.

The stabilization structure can further include a third lateral supportcable positioned below the first lateral support cable, a fourth lateralsupport cable positioned below the second lateral support cable andspaced apart from the third lateral support cable, a third stabilizationcable positioned below the first stabilization cable and coupled to thethird lateral support cable and coupled to the fourth lateral supportcable, and a fourth stabilization cable positioned below the secondstabilization cable and coupled to the third lateral support cable andcoupled to the fourth lateral support cable.

A rocket landing stabilization system can further comprise a hookcoupled to a rocket, the hook configured to engage the stabilizationstructure. The stabilization structure can include a clamp system. Theclamp system can include a plurality of jaws. A rocket landingstabilization system can further comprise a body of water under thestabilization structure. The funnel can float on the body of water. Thefunnel can be coupled to at least one propeller to enable the funnel tobe repositioned by the propeller.

A method of stabilizing a landing rocket can comprise landing the rocketon a funnel and actuating a stabilization structure positioned above thefunnel. Actuating the stabilization structure can include moving a firststabilizing cable toward a second stabilizing cable until the rocket isheld between the first and second stabilizing cables. The method canfurther comprise engaging a hook coupled to the rocket with thestabilization structure. Actuating the stabilization structure caninclude clamping the rocket between a plurality of jaws. Thestabilization structure can be positioned above a body of water. Thefunnel can be floating on the body of water. The method can furthercomprise using a propeller coupled to the funnel to move the funnelthrough the body of water.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates a rocket landing at a land-based landing site.

FIG. 2 illustrates a rocket landing at a sea-based landing site.

FIG. 3 illustrates a first rocket landing stabilization system.

FIG. 4 illustrates a second rocket landing stabilization system.

FIG. 5 illustrates a third rocket landing stabilization system.

FIG. 6 illustrates a fourth rocket landing stabilization system.

FIG. 7 illustrates a fifth rocket landing stabilization system.

FIG. 8 illustrates components of a sixth rocket landing stabilizationsystem.

FIG. 9 illustrates a seventh rocket landing stabilization system.

FIG. 10 illustrates the rocket landing stabilization system of FIG. 9with peripheral walls removed.

FIG. 11 illustrates a cradle component of the rocket landingstabilization system of FIGS. 9-10 .

FIG. 12 illustrates a cross-sectional view of the cradle component ofFIG. 11 .

FIG. 13 illustrates an oblique cross-sectional view of the cradlecomponent of FIGS. 11-12 .

DETAILED DESCRIPTION

FIG. 1 illustrates a rocket 2 landing on the ground at a land-basedlanding site 4. FIG. 2 illustrates the rocket 2 landing on a barge 6 inthe ocean at a sea-based landing site 8. In both a land-based and asea-based landing, the rocket 2 includes landing gear 10 that can helpthe rocket 2 come to rest at the landing site. Because of the relativelysmall width to height ratio of the landing gear 10 relative to theoverall height of the rocket 2, and because the center of mass of therocket 2 can be higher than desired when the rocket 2 is attempting toland at a landing site, the rocket 2 can be prone to tip over, causingdamage to or destruction of the rocket 2.

Therefore, as shown in FIG. 3 , a rocket stabilizing structure 12 can beused to stabilize the rocket 2 as it attempts to land at a landing site14. While landing site 14 is illustrated as a land-based landing site14, landing site 14 can in alternative embodiments be a sea-basedlanding site 14. The stabilizing structure 12 includes four uprightsupport structures 16 (e.g., vertical posts or columns) extendingvertically relative to the ground. The upright support structures 16 canbe spaced apart from one another so as to form the four corners of asquare or rectangular configuration with the landing site 14 at itscenter. The upright support structures 16 can be rigid columns made ofsteel, reinforced concrete, or any other suitable materials. In onealternative embodiment, the landing site 14 is enclosed by supportelements, such as by being located below ground level or within asurrounding structure such as a solid cast in place concrete wall inplace of the upright support structures 16. Such a surrounding structurecan include support elements similar to those described below in theform of rails embedded inside protective voids within the surroundingstructure.

The stabilizing structure 12 also includes a set of four lateral supportelements 18, each of the lateral support elements extending between twoof the upright support structures 16 so that the support elements 18form the four sides of the square or rectangular configuration with thelanding site 14 at its center. The lateral support elements 18 can berigid beams or girders made of steel or other suitable materials, or canbe relatively flexible cables or wires made of steel or other suitablematerials. The upright support structures 16 and the lateral supportelements 18 can collectively be referred to as a gantry arrangement or agantry system.

The stabilizing structure 12 also includes a plurality of stabilizingelements 20A, 20B (collectively 20), including a first pair ofstabilizing elements 20A oriented along a first axis X and spanningbetween two opposed lateral support elements 18, and a second pair ofstabilizing elements 20B oriented along a second axis Y perpendicular tothe first axis X and spanning between the other two opposed lateralsupport elements 18. The stabilizing elements 20 can be rigid beams orgirders made of steel or other suitable materials, or can be relativelyflexible cables, straps, wires, or some combination thereof made ofsteel or other suitable materials.

Each end of each of the stabilizing elements 20 can be coupled to one ofthe support elements 18 by a coupling element 22. The coupling elements22 can include mechanical features that couple the ends of thestabilizing elements 20 to the support elements 18 so that the ends ofthe stabilizing elements 20 can be moved independently of each otherlongitudinally along the length of the support elements 18 in acontrolled manner. For example, the stabilizing elements 20 can be movedat high speed along the support elements 18 using high speed belts onencoded motor driven pulleys. A center portion of each of thestabilizing elements 20 can be coupled or tied to a first end of arespective resistive cable (not illustrated). A second end of eachresistive cable opposite to its first end can be coupled to a spring orother resistive apparatus to resist longitudinal motion of the resistivecable. The resistive cables can increase tension in the stabilizingelements 20 to prevent the stabilizing elements from swaying as theymove or impacting a landing rocket at undesirably high speeds. Thecoupling elements 22 can include weak points in the structure 12 suchthat any extreme loading events occurring within the stabilizingelements 20 result in breaking away or decoupling of the couplingelements 22 and separation of the stabilizing elements 20 from thelateral support elements 18 such that extreme loads are not transferredto the gantry arrangement or gantry system.

The coupling elements 22 can include mechanical features that can letout or take in the stabilizing elements 20 to provide slack or tensionto the stabilizing elements 20. Additionally, the stabilizing elements20 can include engagement fittings 70 to engage the rocket 2 in a moreform-fitting manner. In embodiments including such engagement fittings70, the stabilizing elements 20 can be moved along the support elements18 to adjust the location of the engagement fittings 70 to a suitablelocation to embrace the rocket 2. In some implementations, theengagement fittings 70 can move along the length of the respectivestabilizing elements 20. The coupling elements 22 can include encodedmotors to move the stabilizing elements 20 along the support elements18. Additionally, the coupling elements 22 can include mechanicalfeatures that can slow or brake their movement along the supportelements 18 in anticipation of encountering the load of the rocket 2, inorder to prevent excessive stresses being imparted to the high-speedbelts or encoded motor driven pulleys.

A method of landing a rocket such as rocket 2 at the landing site 14 caninclude launching the rocket 2, such as from a land-based or a sea-basedlaunching site. The method can further include controlling the rocket 2such that it follows a controlled launch trajectory, such as into outerspace. The method can further include performing various maneuvers withthe rocket 2, such as to deliver a payload to a desired location, and tochange the orientation of the rocket 2 such that it begins to fall backtoward the earth in an orientation in which its engine faces the earth.The method can further include controlling the rocket 2 such that itfollows a controlled descent trajectory, such as toward the landing site14.

The method can further include actuating the stabilizing elements 20A tomove apart from one another along the lateral support elements 18 andactuating the stabilizing elements 20B to move apart from one anotheralong the lateral support elements 18, such as to bring both sets ofstabilizing elements 20 to protective enclosures such as protectiveenclosure 72 residing on the support elements 18 (only one is shown inFIG. 3 , but one can be provided on each of the support elements 18).The method can further include controlling the rocket 2 such that itbegins a landing sequence at the landing site 14, similar to that shownin FIG. 1 , such that the rocket 2 is positioned between the stabilizingelements 20A and between the stabilizing elements 20B.

The method can further include actuating the stabilizing elements 20A tomove toward each other and actuating the stabilizing elements 20B tomove toward each other, thereby enclosing the rocket 2 within thestabilizing elements 20. The method can further include landing therocket 2 at the landing site 14, such as on the landing gear 10 underthe control of the rocket engine. The stabilizing elements 20 cancontact the rocket 2 to stabilize the rocket 2 and prevent it fromtipping over or damaging the landing gear during the landing, therebypreventing its destruction or deterioration. In some cases, thestabilizing elements 20 do not contact the rocket 2, such as if therocket 2 successfully lands on the landing gear 10.

The stabilizing elements 20 can be moved at high speed, e.g., after thethreat of the rocket's flame has passed below the stabilizing elements20, to within close proximity of, or into contact with, the rocket 2.The rocket stabilizing structure 12 can include sensors that can detector track the location of the rocket 2, and the sensors can be used todetermine X and Y coordinates of the expected landing location of therocket 2. These coordinates can be used to direct the movement of thestabilizing elements 20 such that the stabilizing elements 20 close inon the rocket 2 without pushing it laterally.

The sensors can also trigger the closing of the stabilizing elements 20when the rocket 2 reaches an elevation at which a portion of the rocket2 is between the stabilizing elements 20. In some cases, the closing ofthe stabilizing elements 20 can be coordinated with the descent of therocket 2 such that as the rocket 2 approaches the landing site 14, andhovers over the landing site 14 or descends relatively slowly toward thelanding site 14, the stabilizing elements 20 continuously close in onthe rocket 2. In some cases, tension in the stabilizing elements 20 canincrease as the rocket 2 approaches the landing site 14 and hovers overthe landing site 14 or descends relatively slowly toward the landingsite 14. This can help to prevent heat generated by the rocket 2 fromdamaging the stabilizing structure 12 and the stabilizing elements 20.

FIG. 4 illustrates a stabilization system 24 similar to stabilizingstructure 12, but having a first set of support elements 26 andstabilizing elements 28A, 28B (collectively 28) and a second set ofsupport elements 30 and stabilizing elements 32A, 32B (collectively 32).Both sets of support elements 26, 30 can be coupled to and supported bya set of four upright support structures 34 (e.g., post, columns). Thefirst set of support elements 26 and stabilizing elements 28 can besimilar to the support elements 18 and stabilizing elements 20 and thesecond set of support elements 30 and stabilizing elements 32 can besimilar to the support elements 18 and stabilizing elements 20.

A method of using the stabilizing system 24 can be similar to the methoddescribed above. The method can include actuating each of thestabilizing elements 28A, 28B, 32A, and 32B to move apart from oneanother along the respective support elements 26, 30. The method canfurther include controlling the rocket 2 such that it begins a landingsequence at the landing site 36 such that the rocket 2 is positionedbetween the stabilizing elements 28A, between the stabilizing elements28B, between the stabilizing elements 32A, and between the stabilizingelements 32B. The method can further include actuating the stabilizingelements 28A, 28B, 32A, and 32B to move toward each other so that theyenclose and stabilize the rocket 2. The stabilizing elements 28, 32 canprovide two separate stabilization locations, spaced apart from oneanother along a vertical Z axis perpendicular to the X and Y axes, atwhich the rocket 2 can contact and thereby stabilize the rocket 2. Insome cases the rocket 2 can land without contacting the stabilizingelements 28, 32, such as when the rocket 2 successfully lands on thelanding gear 10. The stabilizing elements 28, 32 can act independentlyof one another, such as to allow the upper set to activate first as therocket descends below the upper set, clearing a safety plane of theupper set, and the lower set to activate second as the rocket descendsbelow the lower set, clearing a safety plane of the lower set.

FIG. 5 illustrates a stabilization system 38 similar to stabilizingstructure 12, but having three upright support structures 40, threelateral support elements 42, and three stabilizing elements 44. Thestabilizing elements 44 can be elastic or have adjustable lengths sothat as they move along the support elements 40 their length can changeto match the changing distance between the support elements 42. A methodof using the stabilizing system 38 can be similar to the methodsdescribed above, including actuating the stabilizing elements 44 to moveaway from one another, positioning the rocket 2 between the stabilizingelements 44, closing the stabilizing elements 44 around the body of therocket 2, and then landing the rocket 2 at the landing site 46.

The stabilizing elements described herein can be straps, wires, cables,or some combination thereof, made of fabric or polymers, and the systemsdescribed herein can be referred to as high speed cable strap arrestsystems, which can be actuated to move as described herein usingelectromagnetically-powered actuators. Any of the systems describedherein can be used to land a rocket 2 at a land-based landing site or ata sea-based landing site, such as on a barge or rocket landing platformin the ocean. In some cases, the stabilizing elements described hereincan be positioned at about half the height of the rocket 2, or at alocation above the center of gravity of the rocket 2. In some cases, afirst set of stabilizing elements can be positioned at about one quarterthe height of the rocket 2 and a second set of stabilizing elements canbe positioned at about three quarters the height of the rocket 2. Insome cases, a first set of stabilizing elements can be positioned atabout one third the height of the rocket 2 and a second set ofstabilizing elements can be positioned at about two thirds the height ofthe rocket 2.

As described above, the rocket 2 can be stabilized by a stabilizationsystem as the rocket 2 lands at a landing site on landing gear 10. Asshown in FIG. 6 , a rocket 48 can include hooks or fins 50 extendinglaterally away from its main body 52. For example, such fins 50 can beused to guide the descent trajectory of the rocket 48. These hooks orfins 50 can be caught on stabilization elements 54 of a stabilizationstructure 56, such that the rocket 48 does not actually directly contactits landing site, but is instead caught or cradled, by the stabilizationelements 54. Such embodiments can eliminate the need for the landinggear altogether such that the rocket 48 can have no landing gear,thereby reducing the weight and complexity of the rocket 48.

In such embodiments, the stabilization elements 54 can have sufficientstrength to catch and hold the rocket 48. In some cases, couplingelements (e.g., coupling elements 22) can be provided with a clutchsystem to feed out additional length of the stabilization elements 54and to retract excess length of the stabilization elements 54 as needed,to further cradle the rocket 48 and provide a soft controlled landing.In embodiments in which a stabilization structure 56 is designed tocatch the rocket 48, the rocket 48 can be provided with landing gear asa back-up or safety feature.

As shown in FIG. 7 , a rocket stabilizing system 60 can include anadditional set of support elements (not illustrated) and an additionalset of stabilizing elements 58 positioned close to the landing sitevertically. A rocket 62 can in some cases come to rest on thisadditional set of stabilizing elements 58, which can help the rocket 62to self-center. For example, the additional set of stabilizing elements58 can support a large funnel or hollow tapered body 64 having a flangeor open ring 66 positioned at a relatively small, bottom openingthereof, and the rocket 62 can come to rest on the flange 66 of thefunnel 64 while exhaust from the rocket 62 can flow through the funnel64. The stabilizing elements 58 can be actuated to move the funnel 64along the x-, y-, or z-axes. For example, the rocket stabilizing system60 can include a clutch that can be actuated to allow the funnel 64 tobe moved along the z-axis.

In some cases, the rocket 62 can descend into the funnel 64, and can beguided downward by the funnel 64 until it comes to rest therein. Thefunnel 64 can have a height of several meters or even up to the lengthof the rocket 62, such that the rocket 62 can be completely enclosed andcradled within the funnel 64. The rocket 62 can be provided with rollerbearings or chamfered surfaces of a relatively lubricious material atits bottom end so as to smoothly and safely engage with the funnel 64 asit lands. The additional set of support elements, additional set ofstabilizing elements 58, or the funnel 64 can be vertically adjustablealong the Z axis to further cushion the rocket 62 as it lands. Forexample, the funnel 64 can be moved in the Z axis at a rate that is aconstant percentage of the Z axis velocity of the rocket 62.

In some cases, the funnel 64 or the flange 66 can have a first matingsurface and the rocket 62 can have a second mating surface complementaryto the first mating surface so that the funnel 64 or flange 66 can matewith the rocket 62 when the rocket 62 lands at the landing site. In somecases, the funnel 64 can include one, two, three, or more jaw features68, such as mounted to a flange at the top of the funnel 64, that can beused to enclose and grasp the rocket 62 as it comes to rest in or on thefunnel 64. FIG. 8 shows an alternative funnel 74 that includes fouralternative jaw features 76 that can be actuated to move toward oneanother, as illustrated by the arrows 78, to enclose and grip or graspthe rocket 62 to stabilize the rocket 62 as it lands. The jaw features68 and 76 can be referred to herein as stabilizing structures.

This additional set of support elements and stabilizing elements 58 canbe formed from very high-strength and heavy cables. The sensorsdescribed above can be used to track the location of the rocket 62 as itdescends toward the landing site and this information can be used toadjust the location of the additional set of stabilizing elements 58 tomatch the location of the rocket 62 as the rocket 62 descends. In somecases, this tracking can be achieved using triangulation of data fromcorners of the stabilization structure 60 to determine an accuratelocation, and data regarding orientation of the rocket 62 can beprovided by accelerometers onboard the rocket 62. These features canreduce or eliminate the need for landing gear and the rocket 62 can haveno landing gear in some cases.

In some embodiments, the support elements described herein, such as thelateral support elements 18, 26, 30, or 42, can be vertically adjustablein the Z axis along the respective upright support structures 16, 34,40. In some embodiments, a body of water and a water distribution systemincorporated within the stabilizing elements, the engagement fittings,or the large funnel type structure can be provided to cool components ofthe rocket 2 or the stabilizing system at the landing site, to preventdamage from excessive heat.

FIG. 9 illustrates a rocket landing stabilization system 100, which canbe used to stabilize a rocket 102 as it lands within the stabilizationsystem 100. The stabilization system 100 can include four uprightsupport structures, such as four peripheral walls 104. The peripheralwalls 104 can comprise reinforced pre-cast concrete, iron, steel, orother suitable materials. In some implementations, the stabilizationsystem 100 can be located on land with the peripheral walls 104supported on a foundation structure. In other implementations, thestabilization system 100 can be located at sea, and can be configured tofloat in water. For example, the stabilization system 100 can include aclosed bottom end spanning between the four peripheral walls 104 so thatthe stabilization system 100 forms a large floating barge. As anotherexample, the stabilization system 100 can include an open bottom so thatan internal space of the stabilization system 100 is open to the sea onwhich it floats, and the peripheral walls 104 can be hollow or coupledto separate floatation devices so that the stabilization system 100forms a large floating barge.

FIG. 10 illustrates the stabilization system 100 with the peripheralwalls 104 removed so that internal components of the stabilizationsystem 100 are more clearly illustrated. As illustrated in FIG. 10 , thestabilization system 100 includes a first set of support elements 106and a first set of stabilizing elements 108, as well as a second set ofsupport elements 110 and a second set of stabilizing elements 112. Thesesupport elements 106, 110 and stabilizing elements 108, 112 can includethe same features and function in the same or similar ways as describedelsewhere herein, such as with respect to similar components illustratedin FIG. 4 . Coupling elements similar to the coupling elements 22described above can couple the stabilizing elements 108, 112 to therespective support elements 106, 110, and can include actuators toactuate motion of the stabilizing elements 108, 112, ratcheting brakesystems to absorb loads resulting slowing motion of the stabilizingelements 108, 112, rack systems to prevent such loads from beingtransferred to the actuators, and clutch systems to reduce tension inthe stabilizing elements 108, 112. In some implementations, the secondset of support elements 110 and second set of stabilizing element 112can be omitted or replaced by a clamp system similar to the jaw features68 or 76 described with respect to FIGS. 7 and 8 . In someimplementations, the first and second sets of support elements 106, 110,can be at least partially embedded or enclosed within the peripheralwalls 104 to protect the support elements 106, 110 as the rocket 102lands.

FIG. 10 also illustrates that the stabilization system 100 can include abody of liquid, such as a body of water 116 that spans between thebottom portions of the peripheral walls 104. In implementations in whichthe stabilization system 100 is located on land, the body of water 116can comprise an artificial pond formed within the stabilization system100. In implementations in which the stabilization system 100 is locatedat sea and includes a closed bottom end, the body of water 116 cancomprise water from any source. For example, the body of water 116 caninclude salt water pumped into the stabilization system 100 from thesurrounding body of water on which the stabilization system 100 floats.As another example, the body of water 116 can include freshwater pumpedinto the stabilization system 100 prior to the stabilization systemleaving port. In some cases freshwater is preferred to salt waterbecause freshwater results in reduced corrosion. In implementations inwhich the stabilization system 100 is located at sea and includes anopen bottom end, the body of water 116 can comprise water that entersthe stabilization system 100 from the surrounding body of water on whichthe stabilization system 100 floats.

FIG. 10 also illustrates that the stabilization system 100 can include acradle 114 that can float within the body of water 116. FIGS. 11 through13 illustrate the cradle 114 in greater detail. As illustrated in FIG.11 , the cradle 114 can include a top funnel or inverted cone 118, whichcan function in ways similar to those described above with respect tofunnels 64 and 74 illustrated in FIGS. 7 and 8 . The top funnel 118 cancomprise a two-inch thick steel plate, while other components of thecradle 114 can comprise one-inch thick steel plate material. The cradle114 can include a second funnel 120 having either the same or differentdimensions as the top funnel 118 located below and separated from thetop funnel 118 by a predetermined distance, to form a conically-shapedexhaust passage 122 between the top funnel 118 and the second funnel120. A plurality of supporting plates 124 can be coupled at respectivefirst ends to the top funnel 118 and at respective second ends oppositethe first ends to the second funnel 120, such that the supporting plates124 extend vertically between the two funnels 118, 120, to maintain thepredetermined distance and form the exhaust passage 122.

The funnels 118 and 120 can converge as they extend downward and thesecond funnel 120 can be coupled at its bottom end to a neck portion 126of the cradle 114. The neck portion 126 can include a verticallyoriented cylindrical body 128 having a large diameter (e.g., sixteenfoot diameter) and a plurality of coupling plates 130 extending radiallyoutward from the cylindrical body 128. Two coupling plates 130 arevisible in FIG. 11 , but four coupling plates 130, spaced at rightangles from one another around the neck portion 126, can be used. Thecoupling plates 130 can include respective openings 132 to which cables,straps, or wires can be coupled to pull the cradle 114 aroundhorizontally (e.g., along x- and y-axes) within the body of water 116.The coupling plates 130 can be coupled to the cradle 114 at a verticallocation corresponding to a center of balance of the cradle 114, suchthat pulling the cradle 114 using the coupling plates 130 does not pullthe cradle 114 over. In some implementations, the cradle 114 can includetwo sets of coupling plates 130 spaced apart from one anothervertically, such as a first set of coupling plates 130 at the neckportion 126 and a second set of coupling plates 130 at the bottom of thecradle 114, so as to allow two independent sets of cables, straps, orwires coupled to the respective coupling plates 130 to keep the cradle114 vertical or plumb in the body of water 116.

The neck portion 126 can be coupled at its bottom end to avertically-extending cylindrical bottom tank 134. The bottom tank 134can house a plurality of internal conduits 138 and propellers 136, whichcan be used to move the cradle 114 around horizontally (e.g., along x-and y-axes) within the body of water 116. The propellers 136 can allowthe cradle 114 to move around within the body of water 116 autonomously,or under the guidance of an on-board computer control system, such as inresponse to information received regarding the location and trajectoryof the rocket 102 as it is landing on the cradle 114.

FIG. 12 illustrates the cradle 114 in cross-section, and FIG. 13illustrates the cradle 114 in cross-section from an oblique angle, toprovide additional views of some of the components of the cradle 114.For example, FIGS. 12 and 13 illustrate more clearly that the bottomtank 134 houses a system of internal conduits that includes a verticalconduit 138 a extending upward from an inlet at a center of the bottomend of the bottom tank 134 to a junction 140 of the system of internalconduits. The system of internal conduits also includes four horizontalconduits 138, each extending radially outward from the junction 140 tooutlets at a radial periphery of the bottom tank 134. The fourhorizontal conduits 138 can each extend outward from the junction 140along axes at right angles to one another, and can each house arespective impeller or propeller 136. To move the cradle 114 aroundwithin the body of water 116, the propellers 136 can be actuated todrive a flow of water through the conduits 138, 138 a.

FIGS. 12 and 13 also illustrate more clearly that, as the rocket 102lands within the top funnel 118, its exhaust can travel out of the topfunnel 118 through an opening at its bottom end, radially outwardbetween the plates 124, and upward and outward through the exhaustpassage 122 between the funnels 118 and 120. FIGS. 12 and 13 alsoillustrate that an upwardly pointing cone 142 can be positioned at thecenter of the funnels 118 and 120 and between the plates 124. The cone142 can include a plurality of openings 144 through which water can besprayed (e.g., using internal pumps and piping to pump water from thebody of water 116) to cool the exhaust from the rocket 102 as the rocket102 lands on the cradle 114 and the exhaust passes through the exhaustpassage 122.

As the cradle 114 floats within the body of water 116 without the rocket102 situated on the cradle 114, the bottom tank 134 can be positionedunderwater and can be filled with air to provide buoyancy to the rest ofthe cradle 114. The funnels 118 and 120 can be positioned above thewater to allow the rocket 102 to land, and a first water line 146 canextend around the neck portion 126, as shown in FIG. 12 . As the rocket102 lands on the cradle 114, the weight and other forces exerted by therocket 102 can force the cradle 114 to sit deeper in the body of water116, such that a second water line 148 extends around a higher point ofthe neck portion 126, as shown in FIG. 12 . The second water line 148can be generally level with the bottom end of the second funnel 120 andcan be, in some instances, about four feet above the first water line146. Because the cradle 114 floats within the body of water 116, it canmove up and down in the water to cushion the rocket 102 as it lands onthe cradle 114. Once the rocket 102 has landed on the cradle 114, avalve can be opened to allow the body of water 116 to flow into andflood the internal space within the bottom tank 134, so that the cradle114 sinks in the body of water 116 until it rests at the bottom of thebody of water 116. Thus, the rocket 102 can be stabilized after landingto allow it to be more easily removed from the stabilization system 100.

The stabilization system 100 can allow the rocket 102 to land withoutusing landing gear and thus the rocket 102 can omit landing gear. Thelarge body of water 116 can help to dissipate heat from the rocket 102and the cradle 114 as the rocket 102 lands, and in the event of acatastrophic failure or explosion of the rocket 102. Industrial shocksor springs can be incorporated into the stabilization system 100, suchas between the funnels 118, 120 and the neck portion 126, to furthercushion the rocket 102 as it lands. Retractable wheels can beincorporated into the stabilization system 100, such as on the undersideof the cradle 114. Such wheels can be used to autonomously drive, move,or rotate the cradle 114 within the stabilization system 100, such as ona solid surface at the bottom of the body of water 116, to position thecradle 114 prior to the rocket 102 landing on the cradle 114. Once thewheels have been used to position the cradle 114 at a desired locationand orientation, the wheels can be retracted up into the cradle 114 sothat the cradle 114 floats in the body of water 116, as described above.

Aspects, features and/or techniques of the various embodiments describedabove can be combined to provide further embodiments. In addition,aspects of the embodiments can be modified, if necessary to employconcepts of U.S. Pat. No. 8,678,321, and U.S. provisional patentapplication No. 62/153,433, filed Apr. 27, 2015, to which thisapplication claims priority, which are both incorporated herein byreference in their entireties, to provide yet further embodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled.

The invention claimed is:
 1. A rocket landing stabilization system,comprising: a stabilization structure located at a landing site, whereinthe stabilization structure includes a plurality of jaws; and a hookcoupled to a main body of a rocket, the hook extending laterally awayfrom the main body of the rocket, and the hook configured to engage thestabilization structure as the rocket lands.
 2. The rocket landingstabilization system of claim 1 wherein the plurality of jaws areconfigured to grasp the rocket as the rocket lands.
 3. The rocketlanding stabilization system of claim 1 wherein the plurality of jawsare configured to move toward one another to enclose and grasp therocket as the rocket lands.
 4. The rocket landing stabilization systemof claim 1 wherein the stabilization structure includes an uprightsupport structure and a stabilizing element supported by the uprightsupport structure, wherein the stabilizing element is configured tostabilize the rocket as the rocket lands.
 5. The rocket landingstabilization system of claim 4 wherein the stabilization structureincludes a plurality of stabilizing elements supported by the uprightsupport structure, wherein the plurality of stabilizing elements areconfigured to hold the rocket.
 6. The rocket landing stabilizationsystem of claim 5 wherein the plurality of stabilizing elements includesa first stabilizing element and a second stabilizing element that ismovable independently of the first stabilizing element.
 7. The rocketlanding stabilization system of claim 5 wherein the plurality ofstabilizing elements are configured to catch the rocket as the rocketlands.
 8. The rocket landing stabilization system of claim 5 wherein theplurality of stabilizing elements are configured to cradle the rocket asthe rocket lands.
 9. The rocket landing stabilization system of claim 5wherein the plurality of stabilizing elements are configured to beadjusted vertically to cushion the rocket as the rocket lands.
 10. Therocket landing stabilization system of claim 4 wherein the stabilizingelement is made of steel and is rigid.
 11. A rocket landingstabilization system, comprising: a stabilization structure located at alanding site; and a hook coupled to a main body of a rocket, the hookextending laterally away from the main body of the rocket, and the hookconfigured to engage the stabilization structure as the rocket lands;wherein the stabilization structure includes an upright supportstructure and a stabilizing element supported by the upright supportstructure, wherein the stabilizing element is configured to stabilizethe rocket as the rocket lands; wherein the stabilizing element includesan engagement fitting that is movable along the length of thestabilizing element and that is configured to engage the hook.
 12. Arocket landing stabilization system, comprising: a stabilizationstructure located at a landing site, wherein the stabilization structureincludes a clamp system; and a fin coupled to a main body of a rocket,the fin extending laterally away from the main body of the rocket, andthe fin configured to engage the stabilization structure as the rocketlands.
 13. The rocket landing stabilization system of claim 12 whereinthe stabilization structure includes an upright support structure and aplurality of stabilizing elements supported by the upright supportstructure, wherein the stabilizing elements are configured to stabilizeand catch the rocket as the rocket lands.
 14. A method of catching arocket as the rocket lands, comprising: engaging a hook coupled to amain body of the rocket with a stabilization structure located at alanding site, the hook extending laterally away from the main body ofthe rocket; wherein the stabilization structure includes an uprightsupport structure, a first stabilizing element supported by the uprightsupport structure, and a second stabilizing element supported by theupright support structure; wherein the first and second stabilizingelements are movable independently of one another and configured tocatch the rocket as the rocket lands; wherein the first stabilizingelement includes a first engagement fitting that is movable along alength of the first stabilizing element and the second stabilizingelement includes a second engagement fitting that is movable along alength of the second stabilizing element; wherein the method furthercomprises moving the first and second stabilizing elements relative tothe upright support structure, moving the first engagement fitting alongthe length of the first stabilizing element, moving the secondengagement fitting along the length of the second stabilizing element,and using the stabilization structure to move the rocket.
 15. The methodof claim 14, further comprising operating the rocket such that therocket hovers at the landing site.
 16. The method of claim 14, whereinstabilizing the rocket as the rocket lands includes stabilizing therocket as it lands vertically.
 17. The method of claim 14, furthercomprising using the stabilization structure to move the rocket.